Production of single cell protein [SCP] from Egyptian cane sugar molasses III Determination of nucleic and amino acids content, protein fractions and protein digestability of the yeast candida humicola 6

ABSTRACT

In this investigation, the fooder yeast Candida humicola 6 was grown on sugar cane molasses media under aerobic conditions. The obtained biomass was chemically analyzed for the nucleic acids [RNA and DNA] and the true protein and nonprotein nitrogen content. Also, the yeast protein fractions and the amino acid content of each protein fraction and the whole biomass were determined. Besides, the protein digestibility by the proteolytic enzymes was determined [in vitro]. The results indicated that the yeast cells contained 5.99% nucleic acids, 37.4% true protein and 52.4% crude protein at the end of the logarithmic phase. The highest amount of protein fractions was that of the alkali fraction, [61.6% of the total cell protein]. The alkali protein fraction was the more rich in all amino acids especially the essential amino acids which were in amounts higher than that given in Food and Agriculture Organization [FAO] pattern. The whole cells were also rich in most amino acids except sulfur-amino acids. The yeast cells protein was characterized by a high digestibility ratio, 77.2%, especially, when the cells were inoculated with pepsin in vitro. The above-mentioned results indicate that the biomass of C. humicola 6 can be used in food and feed purposes, the alkali protein fraction which has high nutritional value can also be used as supplement for the poor protein-foods